2 * Rusty Russell (C)2000 -- This code is GPL.
3 * Patrick McHardy (c) 2006-2012
6 #include <linux/kernel.h>
7 #include <linux/slab.h>
8 #include <linux/init.h>
9 #include <linux/module.h>
10 #include <linux/proc_fs.h>
11 #include <linux/skbuff.h>
12 #include <linux/netfilter.h>
13 #include <linux/netfilter_ipv4.h>
14 #include <linux/netfilter_ipv6.h>
15 #include <linux/netfilter_bridge.h>
16 #include <linux/seq_file.h>
17 #include <linux/rcupdate.h>
18 #include <net/protocol.h>
19 #include <net/netfilter/nf_queue.h>
22 #include "nf_internals.h"
25 * Hook for nfnetlink_queue to register its queue handler.
26 * We do this so that most of the NFQUEUE code can be modular.
28 * Once the queue is registered it must reinject all packets it
29 * receives, no matter what.
32 /* return EBUSY when somebody else is registered, return EEXIST if the
33 * same handler is registered, return 0 in case of success. */
34 void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
36 /* should never happen, we only have one queueing backend in kernel */
37 WARN_ON(rcu_access_pointer(net->nf.queue_handler));
38 rcu_assign_pointer(net->nf.queue_handler, qh);
40 EXPORT_SYMBOL(nf_register_queue_handler);
42 /* The caller must flush their queue before this */
43 void nf_unregister_queue_handler(struct net *net)
45 RCU_INIT_POINTER(net->nf.queue_handler, NULL);
47 EXPORT_SYMBOL(nf_unregister_queue_handler);
49 static void nf_queue_entry_release_br_nf_refs(struct sk_buff *skb)
51 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
52 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
55 struct net_device *physdev;
57 physdev = nf_bridge_get_physindev(skb);
60 physdev = nf_bridge_get_physoutdev(skb);
67 void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
69 struct nf_hook_state *state = &entry->state;
71 /* Release those devices we held, or Alexey will kill me. */
79 nf_queue_entry_release_br_nf_refs(entry->skb);
81 EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
83 static void nf_queue_entry_get_br_nf_refs(struct sk_buff *skb)
85 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
86 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
89 struct net_device *physdev;
91 physdev = nf_bridge_get_physindev(skb);
94 physdev = nf_bridge_get_physoutdev(skb);
101 /* Bump dev refs so they don't vanish while packet is out */
102 void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
104 struct nf_hook_state *state = &entry->state;
109 dev_hold(state->out);
111 sock_hold(state->sk);
113 nf_queue_entry_get_br_nf_refs(entry->skb);
115 EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
117 void nf_queue_nf_hook_drop(struct net *net)
119 const struct nf_queue_handler *qh;
122 qh = rcu_dereference(net->nf.queue_handler);
124 qh->nf_hook_drop(net);
127 EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
129 static void nf_ip_saveroute(const struct sk_buff *skb,
130 struct nf_queue_entry *entry)
132 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
134 if (entry->state.hook == NF_INET_LOCAL_OUT) {
135 const struct iphdr *iph = ip_hdr(skb);
137 rt_info->tos = iph->tos;
138 rt_info->daddr = iph->daddr;
139 rt_info->saddr = iph->saddr;
140 rt_info->mark = skb->mark;
144 static void nf_ip6_saveroute(const struct sk_buff *skb,
145 struct nf_queue_entry *entry)
147 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
149 if (entry->state.hook == NF_INET_LOCAL_OUT) {
150 const struct ipv6hdr *iph = ipv6_hdr(skb);
152 rt_info->daddr = iph->daddr;
153 rt_info->saddr = iph->saddr;
154 rt_info->mark = skb->mark;
158 static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
159 unsigned int index, unsigned int queuenum)
161 int status = -ENOENT;
162 struct nf_queue_entry *entry = NULL;
163 const struct nf_queue_handler *qh;
164 struct net *net = state->net;
165 unsigned int route_key_size;
167 /* QUEUE == DROP if no one is waiting, to be safe. */
168 qh = rcu_dereference(net->nf.queue_handler);
176 route_key_size = sizeof(struct ip_rt_info);
179 route_key_size = sizeof(struct ip6_rt_info);
186 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
192 if (!skb_dst_force(skb) && state->hook != NF_INET_PRE_ROUTING) {
197 *entry = (struct nf_queue_entry) {
201 .size = sizeof(*entry) + route_key_size,
204 nf_queue_entry_get_refs(entry);
206 switch (entry->state.pf) {
208 nf_ip_saveroute(skb, entry);
211 nf_ip6_saveroute(skb, entry);
215 status = qh->outfn(entry, queuenum);
218 nf_queue_entry_release_refs(entry);
229 /* Packets leaving via this function must come back through nf_reinject(). */
230 int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
231 unsigned int index, unsigned int verdict)
235 ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
238 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
245 EXPORT_SYMBOL_GPL(nf_queue);
247 static unsigned int nf_iterate(struct sk_buff *skb,
248 struct nf_hook_state *state,
249 const struct nf_hook_entries *hooks,
252 const struct nf_hook_entry *hook;
253 unsigned int verdict, i = *index;
255 while (i < hooks->num_hook_entries) {
256 hook = &hooks->hooks[i];
258 verdict = nf_hook_entry_hookfn(hook, skb, state);
259 if (verdict != NF_ACCEPT) {
261 if (verdict != NF_REPEAT)
272 static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
275 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
277 return rcu_dereference(net->nf.hooks_bridge[hooknum]);
280 return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
282 return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
291 /* Caller must hold rcu read-side lock */
292 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
294 const struct nf_hook_entry *hook_entry;
295 const struct nf_hook_entries *hooks;
296 struct sk_buff *skb = entry->skb;
297 const struct net *net;
302 net = entry->state.net;
303 pf = entry->state.pf;
305 hooks = nf_hook_entries_head(net, pf, entry->state.hook);
307 nf_queue_entry_release_refs(entry);
309 i = entry->hook_index;
310 if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
316 hook_entry = &hooks->hooks[i];
318 /* Continue traversal iff userspace said ok... */
319 if (verdict == NF_REPEAT)
320 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
322 if (verdict == NF_ACCEPT) {
323 if (nf_reroute(skb, entry) < 0)
327 if (verdict == NF_ACCEPT) {
330 verdict = nf_iterate(skb, &entry->state, hooks, &i);
333 switch (verdict & NF_VERDICT_MASK) {
337 entry->state.okfn(entry->state.net, entry->state.sk, skb);
341 err = nf_queue(skb, &entry->state, i, verdict);
353 EXPORT_SYMBOL(nf_reinject);